Effects of different feed components and the treatment of the litter on the ammonia emission of equine urine

Abstract

The main goal of our research was to study the effects of different feed components and the treatment of the litter on the NH3 emission of equine urine. Four adult horses were used in the experiment. The basic diet consisted of 1500 g mashed oat, fed twice a day (morning and evening), and ad libitum hay. During the night the horses were kept separately in concrete floor boxes, the litter was wheat straw. The whole study was divided into 3 main periods. In the first period of the experiment the litter and the floor were treated with a probiotic supplement for two days in the evenings. In the second period of the experiment for 8 days the basic diet was supplemented with 40 ml of probiotic added to the oat. Before the third period of our study the horses were fed with their regular diet for two weeks. After that the oat was changed to a high-protein-value horse feed for 12 days. At the end of the second and third periods, the litter was treated again. Urine contaminated straw samples were collected after each period before and after the litter treatments from different places of the litter in the morning before the daily littering. From the samples, the dry matter content and the NH3 emission were measured. Statistical analysis was carried out with linear modelling. According to our results, both the probiotic treatment of the feed and the high-protein-value horse feed decreased the urine NH3 emission significantly (p<0.05). However, the NH3 emission was only slightly influenced by the litter treatment. Only in the case of probiotic feed supplement could a decrease in emission be detected, but the result was not significant. There was no difference in the dry matter content of the samples. Based on our results, we can conclude that both the high-protein-value horse feed and the probiotic supplement applied in our experiment can be useful to decrease urine NH3 emission by horses. The two-days litter treatment however seems to be too short to gain any positive effects.